#/bin/bash

# Read domains form stdin and echo the ones resolved successfully

server=""
if [ "$#" -ge 1 ] && [ -n "$1" ] ; then
	server="$1"
fi	

first=true
while read line; do
	for domain in $line ; do
		host "$domain" $server &>/dev/null
		if [ "$?" -eq 0 ] ; then
			if "$first" ; then
				first=false
			else
				echo -n ' '
			fi
			echo -n "$domain"
		fi
	done
done
exit 0